Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.

User Name:

Password

Please enter a password for your user account. Note that passwords are case-sensitive.

Password:

Confirm Password:

Email Address

Please enter a valid email address for yourself.

Email Address:

Log-in

User Name

Remember Me?

Password

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Additional Options

Miscellaneous Options

Automatically parse links in text

Automatically embed media (requires automatic parsing of links in text to be on).

Automatically retrieve titles from external links

Topic Review (Newest First)

11-08-2012 07:01 PM

oldbogie

Quote:

Originally Posted by Billgt63SS

On a High Horsepower 350 pump gas what is better?

Depends a whole lot on where in crankshaft degrees the cam shuts the intake. A high horsepower engine usually means a really big cam, this looses a lot of torque off the bottom end that needs to be restored; the method of recovery is through higher than expected compression. Obviously 93 unleaded does impose an upper end to the squeeze, but none the less you're probably going to be shoved to push the limits.

Gearing including the result of tire size and vehicle weight as well as the end use of the machine will also impose restriction or open possibilites. Stiff gears and light weight combine to let you run more compression than what would otherwise be expected. Drag racing will let you may even require you to push the limits harder. Round track especially in the dirt will also let you push harder. Paved round track and road course will force a back off of the upper limit because of the better traction and the possibility of hauling the revs up in the wrong gear which will overload the engine and push the detonation limit sooner. A hot street engine will also have to be more conservative on compression, especially if you mix it with higher gear ratios. Off road tends to use large diameter tires, these unless you really hang some nasty gears in the rear end, will also drive a more conservative compression solution.

So to be of any real help I'd have to know a whole lot more of what's in-store for this high ouput 350.

Bogie

11-06-2012 02:10 PM

techinspector1

Quote:

Originally Posted by cobalt327

Flat top pistons combined w/the chamber volume needed to get your target compression ratio is the best formula in nearly every case.

^^^^times 2

11-05-2012 09:01 PM

1Gary

Still there is a case for not going much over a 8.5 DCR.

11-05-2012 08:25 PM

cobalt327

Quote:

Originally Posted by Billgt63SS

On a High Horsepower 350 pump gas what is better?

Flat top pistons combined w/the chamber volume needed to get your target compression ratio is the best formula in nearly every case.

There may be an argument made for an inverted dome piston combined w/the chamber volume needed for the target CR, but generally speaking a FT w/a smaller chamber will give better flame propagation and a cleaner burn w/better quench/squish action than an open chamber and a dome.

The shape of the chamber is also an important part of it all. A heart or kidney shaped chamber having a larger area quench pad and a more central spark plug location biased towards the exhaust valve (like on the Fast Burn and Vortec heads seen on the right, below) will give a better quench/squish action and detonation resistance than even the earlier small chamber SBC heads (like the fuelie heads, left below) w/FT pistons.

11-05-2012 07:21 PM

Billgt63SS

What's best on a 355 domes and open or flatop and closed? Runnin 93 oct